This invention relates generally to the field of electromedical transducers and more particularly to attachment of medical transducers to blood vessels.
In the past, medical researchers have utilized ultrasound crystals in experimental settings in various combinations and arrangements in order to monitor blood flow or measure cardiac stroke volume. In some cases, such measurements were accomplished by use of ultrasound crystals mounted on catheters passed within blood vessels and veins, and in other cases crystals have been attached to the exterior of the heart or blood vessels. Such attachment has in the past involved suturing the transducer bearing the ultrasound crystal directly to the heart or blood vessel, or suturing a loop or pocket to the heart or blood vessel for retaining the transducer. These procedures are time consuming and difficult. More importantly, the requirement of suturing poses a serious risk, especially in the context of attachment of the transducer to a blood vessel such as the aorta, which typically has a wall thickness of less than 3.2 mm.
The present invention provides a transducer head adapted for use as a doppler flowmeter, which avoids complications and problems due to the use of sutures as an attachment method. The transducer head of the present invention employs two parallel fixation wires which serve to affix the transducer to the desired blood vessel without danger of piercing its wall. The fixation wires also allow for a transducer which requires considerably less time and effort to use than previous transducers which had to be sutured to the blood vessel.
The present invention is believed particularly useful in monitoring blood flow during open heart surgery. Because time and safety considerations are paramount during open heart surgery, it is desirable that diagnostic tools used in conjunction with such surgery not pose significant additional time requirements or additional risks to the patient. The present invention by means of its novel fixation apparatus provides a transducer which meets this criteria, and moves the ultrasound blood flowmeter from the laboratory of the medical researcher to the operating room of the clinician.